Monitoring loss or considerable reduction of pulsation in capillary blood vessels is considered to be important for the maintenance of health conditions.
(1) Approach to Hypotension
In general, the term “hypotension” refers to the case where maximum blood pressure is 110 to 100 mmHg or less. Hypotension is classified into the following types: “essential hypotension,” with which no causative disease is found; “orthostatic hypotension”; i.e., a fall in blood pressure that occurs when a person suddenly rises from a recumbent position or stands up, which may cause, for example, dizziness or light-headedness; and “symptomatic hypotension,” which is caused by some disease (e.g., diabetes).
Less attention has been drawn to hypotension as compared with hypertension, which is also a pathological condition related to blood pressure. However, hypotension is known to cause various symptoms, including dizziness, light-headedness, and general malaise. Particularly, in the elderly, there is concern about accidents caused by light-headedness, or progress of dementia, which could occur as a result of reduction of pulse wave propagation through intracerebral blood vessels. Therefore, in the elderly, further attention must be paid to reduction of pulse wave propagation through intracerebral blood vessels.
(2) Approach to Sclerosis of Capillary Artery
As has been reported, pulse wave velocity (PWV) in large- or medium-sized arteries can be used as an index for evaluating the degree of atherosclerosis or coronary artery risk. Specifically, since the wall of a large- or medium-sized artery of a healthy human exhibits elasticity as in the case of the wall of a rubber tube, a pulse wave; i.e., a pulsation of a blood vessel caused by blood pumped out of the heart (propagation of the pulse wave through the blood vessel indicates the presence of blood flow in the blood vessel), is absorbed by the artery wall, and thus PWV tends to be lowered. In contrast, when sclerosis progresses in a large- or medium-sized artery, the wall of the artery becomes hard, and thus a pulse wave is not readily absorbed by the artery wall, and PWV tends to be increased. Thus, PWV in large- or medium-sized arteries has increasingly become of interest as an index for evaluating health conditions.
PWV in a large- or medium-sized artery can be measured by use of, for example, an apparatus for detecting the blood pressure of extremities.